Outraged workers at a council where top managers were awarded huge pay rises in a behind-closed-doors meeting will walk out in protest.

Council workers at Caerphilly have also called for public support in a campaign to get the pay rises rescinded.

Revelations about the increases of up to 30% for 20 senior managers at the authority have caused uproar among staff, most of whom belong to the trade union Unison.

Chief executive Anthony O’Sullivan, pictured , wrote a report that was seen by just five councillors in September in which he argued that top managers, including himself, were underpaid.

Mr O’Sullivan received a pay rise of up to £35,000, putting him, it is believed, on around £158,000.

Caerphilly’s other 68 councillors were not provided with copies of the report and some only heard rumours of the pay rises from staff.

The executive committee of Unison’s 3,500-strong Caerphilly council branch met yesterday to decide its response to the rises and members’ anger.

Following the meeting, Gary Enright, Unison’s Caerphilly branch secretary, said: “Our members are understandably extremely angry about the chief executive’s mammoth pay rise and are not prepared to simply accept the situation.

“It is grossly unfair and insulting to Caerphilly council workers.

“Following discussions with our members throughout the council, Unison has decided to lead a lunch time walkout this Monday.

“We will be calling on all of our members to use their lunch break to participate in the walkout to demonstrate their anger and strength of feeling on this matter.

“We will also be holding a lobby of the Labour group meeting which is taking place this Monday at 5pm.

“We know that it is not only our members who are angry about the chief executive’s pay rise, but also members of the wider community.

“So we are calling on members of the public to stand alongside us on Monday to send a clear message to the council that this pay rise is simply not acceptable.”

Dominic MacAskill, Unison Cymru’s head of local government, said: “We hope that Caerphilly council will sit up and listen to our members and the wider public on this issue.

“People believe in fairness for all, not just for those at the top of the pay scale. The chief executive has basically awarded himself a pay rise which is in excess of what most of our local government members earn in a year.

“Unison will be writing to the Minister for Local Government, Carl Sargeant, to seek his support and to ask that he publicly condemns the chief executive’s pay rise.

“We will also be convening a mass public meeting early in the New Year and will be inviting all local politicians, including the MPs, AMs and councillors, to attend to publicly express their position on the issue.”

Kelly Andrews, regional organiser of the GMB union, which represents around 2,000 Caerphilly council workers, said: “Our members are absolutely appalled by these rises, not only because they are struggling on a pay freeze, but because the increases play up to the image of public sector workers as overpaid fat cats.

“That just isn’t the case for the vast majority of workers, but rises like this – made even worse by the secretive way they were agreed – give Caerphilly council a very bad name.

“We shall work together with Unison and fully support the actions they are proposing.”

Plaid Cymru councillor James Fussell, one of the five members of the Senior Remuneration Committee which approved the rises, issued a statement which said: “I did raise concerns at the meeting, principally over the question of whether the council had consulted the trade unions in connection with the report.

“But I was told that salary levels for chief officers were outside the normal pay bargaining and negotiating system.

“In hindsight, I should have spoken out more strongly against this report but I was just one of five members, the rest being Labour councillors.

“I did not vote for the increases proposed because I recognise it is very difficult to justify in the present economic climate.

“No other councillors, other than members of the committee, received copies of these exempt papers which is unusual and, therefore, were not aware of the existence of the report at the time it went before the full council in October.”

Caerphilly council said it had not received official notification from Unison about the union’s intentions, and therefore did not wish to comment.